Wild animals are animals that aren't pets. Unlike puppies, for example, wild animals live outside of houses and eat things like other animals or grass.
One of the biggest problems you might have if you encounter a wild animal is that it might want to eat you. Only some wild animals want to eat you, and only some of the time, but the likelihood is non-zero. Another big thing they may do that presents some problems is be poisonous, either to touch or taste. So—don't eat them! Also, you may not want to pet them.
Wild animals' danger is largely dependent on which kind of animal they are. For example, a wild squirrel that doesn't have rabies is not probably going to do anything that will harm you. The same could be said for most birds. On the other hand, a wild lion is probably quite dangerous. It all depends on the type of wild animal this particular wild animal is.
However, the generalized danger inherent to the category makes it very easy to mitigate the amount of danger you face when you encounter one. Broadly speaking, it is best not to engage with wild animals at all. If you do, they may become agitated and fight you; if they don't fight you, they will probably run away, which means that they are experiencing danger instead. Because they are dangerous in lots of ways, we're going ahead and calling wild animals pretty dangerous.
